Minn. Stat. § 508A.84: INSTRUMENTS OF ENCUMBRANCE; DISPOSAL.

The registrar of titles is authorized to destroy instruments of encumbrance which have been satisfied of record or extinguished by operation of law for a period of five years, together with the assignments and satisfactions of them. When the discharge of an encumbrance is by virtue of a judicial or statutory sale, the instruments evidencing the encumbrance of the foreclosure of it, shall not be destroyed until six months after entry of an unappealed order for issuance of a new CPT to the purchaser at the sale or to the purchaser's assignee. Nothing herein contained shall relieve the registrar from maintaining the books and index records required under sections 508A.34 and 508A.37.